Imaging plate cassette for extended X-ray photographs

ABSTRACT

A method of taking an extended X-ray photograph by using an film cassette devised to contain a longer X-ray film such that a longer complete image of a subject may be rendered such that no diagnostic information is lost in examinations of scoliosis or the long bones of the body. When the cassette is exposed to X-rays through an object, an X-ray transmission image of the object is recorded on a stimulable phosphor sheet and, at the same time, the X-ray film is exposed to light instantaneously emitted from the stimulable phosphor sheet upon exposure to X-rays to record an extended photographic latent image of the X-ray transmission image of the object on the X-ray film.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. Provisional Appl. Ser.No. Provisional Patent Application Ser. No. 60/226,709, filed Aug. 18,2000 under 35 U.S.C. §111(b).

FIELD OF THE INVENTION

[0002] The invention generally pertains to an X-ray film cassetteapparatus. More particularly, the invention relates to an modified x-rayfilm cassette holder that provides for the use of extended length filmand/or overlapping imaging plates such that complete x-ray images can beprovided for the spine or long bones of the body.

BACKGROUND OF THE INVENTION

[0003] X-rays photographs are generated through the exposure of x-raysensitive film or imaging elements to the penetrating electromagneticradiation of accelerated electrons suddenly stopped in their trajectoryby collision with a solid body. In this fashion x-rays typically passthrough soft tissue of the body but will by stopped by denser structuressuch as bone and some tumors. These features then allow x-rayradiography techniques to aid in the diagnosis and treatment of injuriesor other ailments.

Computed Radiography

[0004] In computed radiography, a photographic element has an imageformed upon its surface by x-rays, and the element is subsequentlyprovided to a reader where the photographic element is stimulated toemit a radiation pattern that is captured for storage and use. ComputerRadiography (CR) utilizes a phosphor screen with energy storagecapability as an X-ray image receptor. The screen is contained instandard size radiographic cassettes and in integrated imaging stands ortables. The cassettes can be used in existing radiographic tables andstands.

[0005] Cassettes of the kind used in computed radiography may comprise acontainer having upper and lower parts that are hinged together so thatthey can be opened for insertion of a thin, flexible film sheet or rigidfilm plate comprising the photographic element. The cassette is closedand latched so that the cassette with the element therein can be usedwith an x-ray apparatus to produce an image on the photographic element.Then the cassette is taken to a reader where the cassette must be openedand the photographic element extracted by suitable feeders, such assuction feeding devices. The photographic element separate from thecassette is transported through the reader where it is stimulated toemit a radiation pattern and subsequently erased before being returnedto the cassette for re-use.

[0006] This technology offers diagnostic quality advantages overconventional film/screen methods and decreases in the time required forprocessing. Advantages of computed radiography include energysubtraction, which makes it possible to view bone-only and softtissue-only images of the chest, dynamic range control and gradationprocessing, which makes it possible to see both bone and soft tissue onthe same image.

[0007] With dynamic range control, the cassettes are transferred to areader system, or in the case of integrated devices, the reading sectionof the device. Here the imaging plate is scanned with a finely-focusedlaser beam which stimulates luminescence proportional to the local X-rayexposure. The luminescence signal is converted to an electrical signaland is thereby digitized. The data representing the image is subjectedto digital signal processing to optimize the diagnostic content of thevisualized data. The image can be recorded on laser printed filmtransmitted or stored digitally.

[0008] Gradation processing is done via computer to optimize imagecontrast and optical density. Image contrast can be adjusted as desired,in accordance with the anatomical region and diagnostic purpose.

[0009] Energy subtraction expands diagnostic capabilities by providing auser with three views instead of just one: the standard radiograph, abone subtracted radiograph and a soft tissue subtracted radiograph.

Cassette Construction

[0010] Typically an X-ray film cartridge is composed of a rectangularcartridge body and a rectangular cover hinged to the body. The cover islocked by means of a pair of latches mounted to one side of the coveropposite to the side hinged to the body. Often, a cushion pad isinterposed between the cover and at least one intensifying sheetattached to the cover so as to press the intensifying sheet against theX-ray film. The cover is of rectangular shape and has hinges on one sideedge thereof and latch means on the opposite ends thereof. The hinge isusually composed of a pair of hinges to pivotally mount the cover at oneside thereof to the body, and the latch typically is composed of a pairof latches slidably mounted to the cover to be engaged with a pair ofslots provided in one side wall of the cartridge body. Therefore, thehinged cover is held to the cartridge body at four points.

[0011] The above described conventional X-ray film and film cassette,whether viewed as a typical x-ray photograph or digitized throughcomputer radiography techniques, has a defect in that the film orvisualizing element fitting within the cassette is generally not longenough to provide a full view of the spine (e.g. for scoliosis patients)or the other long bones of the body. To remedy this situation the priorart has relied multiple and sequential x-ray exposures or other moreexpensive procedures, such as CT scans or magnetic resonance imaging(MRI). The sequential x-ray photographs of the prior art invariably lefta small portion of the structure to be imaged off the x-ray photographs,leading to a gap in the diagnostic ability of x-ray procedures.Meanwhile, though the more expensive MRI imaging can be used to evaluatethe spinal cord and spinal nerves this capability is often missing fromexisting clinical institutions or is not available on a routine basis.As with all studies, MRI is done for a specific indication andcorrelated with clinical examination. Myelography, a radiographic studywhich uses an injected dye to provide contrast to study the spinal canaland its contents, may also be used for situations in which conditionssuch as scoliosis are suspected but is fairly labor intensive andexposes potential patients to radioactivity for a longer period thantypical x-ray procedures. CT scans are used to provide improveddefinition of abnormalities of vertebral size, shape or number and arealso not always available on a routine basis.

[0012] Accordingly, a need exists to provide a x-ray photograph andcorresponding x-ray film cassette that will provide for routine andimproved x-ray photographs of the spine or other long bones of the body.

SUMMARY OF THE INVENTION

[0013] The primary object of the present invention is to provide anapparatus and method for recording a x-ray image on either a stimulablephosphor screen or imaging plate and on a conventional X-ray film with asubstantially equal intensity of X-rays. The image so recorded is onethat provides an overlapping image so that no diagnostic information islost in a modified cassette holder.

[0014] Another object of the present invention is to provide a method ofrecording a x-ray image of excellent sharpness and resolution both on astimulable phosphor screen or imaging plate and on a conventional X-rayfilm.

[0015] A specific object of the present invention is also to provide acassette for use in conjunction with the method mentioned above.

[0016] Another object of the present invention is to provide an extendedX-ray film imaging plate that is able to obtain a sharp image of anextended body section with a simple structure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1A Shows a side-view of a imaging plate cassette of theinvention in which two standard size cassettes are modified to providefor an extended x-ray image of a target.

[0018]FIG. 1B Shows a edge-view of a imaging plate cassette of theinvention in which two standard size cassettes are modified to providefor an extended x-ray image of a target.

[0019]FIG. 2 Shows two imaging plates of the invention inserted into amodified x-ray cassette in an overlapping confirmation.

[0020]FIG. 3A Shows a tube side view of two imaging plates inserted intoa modified cassette of the invention.

[0021]FIG. 3B Shows a magnified cassette edge view of two imaging platesinserted into a modified cassette holder of the invention demonstratingthe overlap of the imaging plates.

[0022]FIG. 4 Shows the “Z” fold of material that is preferably part ofthe invention.

[0023]FIG. 5 Shows a magnified view of the “Z” fold of material that ispreferably part of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0024] In FIGS. 1 to 5, an X-ray cassette 10 in accordance with anembodiment of the present invention is mainly for recording an X-rayimage of the chest of a human body (not shown) on an X-ray film.

[0025] The cassettes are joined at the bottom and would not be hinged onthe back creating one long cassette with two latch ends. The CF frontmay be replaced with Aluminum strips to strengthen cassette 10.

[0026] Preferably, the invention provides for an x-ray cassette thatwill hold 14″×17″ imaging plates. These imaging plates (e.g. film) mustoverlap inside the cassette in order to prevent loss of image anddiagnostic information. In the prior art, there is a narrow space ontypical x-ray film where no diagnostic information is recorded due tothe space existing between even two sequentially used imaging plates(IP). To resolve this failure the current invention may provide for amodified cassette structure designed to accommodate securely twooverlapping image plates. The top and bottom of the “Z” fold should befolded under the fabric inside the cassette so the IP's do not strikethe edge of the “Z” film when being placed in the cassette. For theoverlapping IP's a “Z” folded sheet of fabric or other suitable materialcan be used as a separator at the junction of the two cassettes.Preferably, the “Z” folded sheet is made of a polyester material. Inaddition the “Z” folded sheet may also be lined on both sides withphosphor imaging materials.

[0027] As previously mentioned, the “Z” film must overlap. Preferably,this overlap is less than 0.5 of an inch. Preferably, the “Z” fold isfabricated out of polyester material.

[0028] To accommodate this change the size of standard cassettes may bealtered to provide for sufficient overlap of imaging plates. Whenemployed in this fashion sequential x-ray photographs retain thefull-length image of a desired object, such as an individuals spine,without loss of any diagnostic information. Typically the cassette willneed to be shortened by up to 1.0 inch to provide sufficient overlap,preferably the modified cassette holder will be shortened by 0.5 inch.

[0029] The method in accordance with the present invention comprisesmaintaining an X-ray film and a stimulable phosphor sheet in closecontact with each other and shielded from light, and exposing said X-rayfilm and said stimulable phosphor sheet to X-rays through an object,whereby a x-ray image of said object is recorded on said stimulablephosphor sheet and, at the same time, said X-ray film is exposed tolight instantaneously emitted from said stimulable phosphor sheet uponexposure to X-rays to record a photographic latent image of the samex-ray image on said X-ray film.

[0030] Thus, it can be appreciated that an x-ray cassette system andfilm therefore have been presented which will facilitate an improvementin the diagnostic use of x-ray photographs, particularly for the spineand the other long bones of an individual animal.

[0031] Accordingly, it is to be understood that the embodiments of theinvention herein providing for an improved diagnostic and informationaluse of x-ray photographs are merely illustrative of the application ofthe principles of the invention. It will be evident from the foregoingdescription that changes in the form, methods of use, and applicationsof the elements of the disclosed x-ray cassette system and associatedelements disclosed may be resorted to without departing from the spiritof the invention, or the scope of the appended claims.

What is claimed is:
 1. A X-ray film cassette device comprising incombination: a rectangular cartridge body having a front wall, a pair ofside walls and a back wall; a rectangular cover hinged at one sidethereof to the back wall of said body by means of a pair of hinge means;a pair of latch means provided at one side of said cover opposite to thehinged side, said latch means being manually operable to be moved from alatching position to a released position; a pair of slots provided inthe front wall of the body to be engaged with said latch means of thecover; at least two imaging plates for recording an image generated byan x-ray source; said at least two imaging plates overlapping so as toprevent the loss of diagnostic information.
 2. The cassette of claim 1,wherein said at least two imaging plates can be processed by a computedradiography reader without manually removing imaging plates fromcassette.
 3. The cassette of claim 1, wherein said system works in a FCR5000 CR Reader imaging device.
 4. The cassette of claim 1, furthercomprising indicia marks on said imaging plates such that said imagingplates can be automatically aligned.
 5. The cassette of claim 1, whereinsaid at least two imaging plates are separated by a “Z’ fold of materialsufficient to prevent said overlapping image plates from coming intodirect contact with each other.
 6. The cassette of claim 1, wherein saidimaging plates are 14″×17″ in dimension.
 7. X-ray film that can be usedin the cassette device of claim
 1. 8. A photostimulable phosphor sheetthat can be used in the cassette device of claim
 1. 9. The x-ray imagesgenerated by the use of the cassette device of claim
 1. 10. The cassetteof claim 1, wherein said system works in any Fuji CR Reader imagingdevice.
 11. A X-ray cassette device comprising in combination: arectangular cartridge body having a front wall, a pair of side walls anda back wall; a rectangular cover hinged at one side thereof to the backwall of said body by means of a pair of hinge means; a pair of latchmeans provided at one side of said cover opposite to the hinged side,said latch means being manually operable to be moved from a latchingposition to a released position; a pair of slots provided in the frontwall of the body to be engaged with said latch means of the cover; atleast two imaging plates for recording an image generated by an x-raysource; on a photostimulable phosphor sheet said at least two imagingplates overlapping so as to prevent the loss of diagnostic information.12. The cassette of claim 11, wherein said at least two imaging platescan be processed by a computed radiography reader without manuallyremoving imaging plates from cassette.
 13. The cassette of claim 11,wherein said system works in a FCR 5000 CR Reader imaging device. 14.The cassette of claim 11, further comprising indicia marks on saidimaging plates such that said imaging plates can be automaticallyaligned.
 15. The cassette of claim 11, wherein said at least two imagingplates are separated by a “Z’ fold of material sufficient to preventsaid overlapping image plates from coming into direct contact with eachother.
 16. The cassette of claim 11, wherein said imaging plates are14″×17″ in dimension.
 17. X-ray film that can be used in the cassettedevice of claim
 11. 18. A photostimulable phosphor sheet that can beused in the cassette device of claim
 11. 19. The x-ray images generatedby the use of the cassette device of claim
 11. 20. The cassette of claim11, wherein said system works in any Fuji CR Reader imaging device.